Telegraph system



June 27, 1950 H. CHIREIX TELEGRAPH SYSTEM Filed Dec. 26, 1946 2 Sheets-Sheet 1 Nil/Z177 INVENIOR Jicmw Clurpw ATTORNEY .Eune 27, 19 50 H. CHlRElX 2,512,763

TELEGRAPH SYSTEM Filed Dec. 26, 1946 2 Sheets-Sheet 2 F'fi 1. w m

ILIULILJU uuur ATTORNEY i atente cl June 27, 1959 TELEGRAPH SYSFEEM Henri Chi-reix, Paris, France, assi-gnor to Gompagnie-Generaledc Telegraphic Sans FiI, a'cor .poration of;France Application December 26, 1946,.Serial No...718,51.0

InFrancejNovember 16, 119,39,

Section 1, Public-Law 690, =August 8, 1946 Patentzexpires, November 16, 11959;

4 Claims. (c1. 178,-2)

In the Morse system, Baudotsystem and the like it is known to define as a time unit, or telegraphic time the duration of theshortest signal. The letters, or signals, are then formed by a certain number of signals which as such correspond with acertain number of telegraphic times-and which succeed one another in a certain number of telegraphic times, Thus, in the Morse code generally employed a dot corresponds with one telegraphic time, a dash corresponds with three telegraphictimes and likewise an interval between letters corresponds with three telegraphic times and an-interval between words to five telegraphic times. In the Baudot code a letter is always characterized by telegraphic times and the emissions correspond with one, or several dots of a duration equal to one telegraphic time period. The Origin of one telegraphictime period can then be marked by a transitory rule residing in the application, or cessation of a signal, or by no occurrence at all if the code employed demands that at this instant nothing should take place.

In accordance with; the present invention, for the transmission of intelligence, means are provided for sending of brief current impulses which are transmitted along the line (by the; station antenna in case of radio transmissions) ahead of the telegraphic times and of same sense and only at the beginning of those characterized precisely by the absence, in-thecode employed; of,

variations of the system (for instance, in the DAOISGsCOdB at the beginning of the seconcband third telegraphic times corresponding with a. mark or a dash, or with a space or an interval between letters). Means are provided for-codiiying the intelligence to be transmitted inaccordance with dots, dashes and spaces which are commensurate with the elementalsignal-periods and odd multiples thereof.

These brief current impulses received -atthe end of the line (or at thestation receiver output in the case of transmissionby radio) will have as their effect the blocking ofsynchronouslocally derived periodic electrical; impulses which are delivered during alternate ones of a succession of elemental signalling-periods. The locally derived impulses are likewise of brief'duration and emitted at the beginning of the telegraphic times, but being shiftable by said impulses alternately positive-and negative and actuating a relay to a condition of spacing significance and a condition' of marking significance. Arelay operating under-such conditions has long been known in telegraphy (Gulstadre1ay). I

Under-these condition it isseen that at the beginningof thetelegraphic times characterized,

inthe, code employed, by a change in'theasystem, thereceiving relay will see-saw in view of the fact that no impulse will stopit, while on the contrary the short impulses, transmitted while no change inthe system occurs-in the; codetransmitted, will block, the-receiving: relay in theposition primitively attained; The; imprinter controlled by, the receivin ;re lay thus, willreproduce,

thezcode of the starting, 7

The advantages.- of the ssystem, whose above exposition describes @theprinciple, are principally evidenced in the case oi radio transmissions on short waves andcan be-br-iefiy summarized as follows:

;1. The emission requiring but a small fraction of thetotal time, thereis realized ant-important saving in theconsumed power and the. instantaneouspower can be generally increasedto a.

definite extent. I 2. The Sys em issecret uptoa certain-point. 3. The mutilationof the signalsowing totali-v mg; effectsand to echoeffects largelyelimi:

nated owing tothe fact that only the wavehaving followed the shortest path releases the receiving.

operation. N

A ;.'particu1arly simple embodiment ofthe invention vtowhich the latter-isnot limited, "however, will now be-describedby way of example.

In; the, drawing Figure 1 represents a portion of the transmitter circuit,

Fig. 2 represents a; portion of the receiver ircui Fig. 3 is a graphic diagram of the-relay receiving telegraphic periods in the absence of;-receiving impulses,

Fig. 4 is a. graphic diagram of the relay when a dash has been receivedequal to three times the telegraphic ,period with the relaycontacts dwelling in a a position a,

Fig. 5 isagraphic-diagram of the relay when a dash has. been; receivedequal to three; times a telegraphic period with relay contacts dwelling in a, position b,

Fig. -6 illustrates a-part'of'the Morse codesig nificant :of-the lettersi am, I

Fig. '7 represents the transmission of the let.- tersaixam of Fig. 6, and- Fig. -8 represents the relay movement for. the letters i am.

There is a tWO position contact-number indi-, cated by l'inFig, 1 whichis aiormofan impulse type transmitter controlledby .a perforated tape. Such transmitter closes the contacts (1,1 or. In .only at the moment in which the pecker-pins ..enter theperforations of the tape, i. e., during. ajrather small fraction-of the telegraphic times.

The. embodiment herein descrihedwillQbe .un-i

derstood by those skilled in the art to be best adapted to a system in which the transmitting tape has two rows of perforations; those in one row defining the front edge of a marking signal, and those in the other row defining the front edge ofa spacing signal. The two pecker-pins which are aligned with the two rows of perforations control the contact member 21 in such manner that contacts a are closed at the commencement of a marking signal, and contacts I) are closed at the commencement of a spacing signal. fore, always followed by a tape perforation in the other row. But these perforations are spaced apart in accordance with the occurrence of dots, dashes and spaces of different duration.

A distributor switch 2 is driven in synchronism with contacts I and closes the voltage source 3 at each telegraphic time during a time which is shorter than that during which the contacts a, or b are established. By means of the brush 25 the contacts of the distributor 2 can be closed during a portion of the contacting times at a and b. The voltage source 3 feeds across the resistances 4 and 5, the screen grid of a multi-electrode tube 6 whose control grid is. fed with tone frequency through the transformer 1 and is suitably biased by the direct current source 8.

The plate is connected to an output transformer 9 and to a voltage source it which may,

then at the terminals of the secondary of the transformer 9 a potential impulse of tone frequency.

However, at the moment where there occur perforations in the band, the contacts then established in a, or in b, short circuit the resistance 5. The current impulses traversing the distributor and whose value is limited by the resistance 4, no longer can unblock the tube 6.- Thus no impulse manifests itself at the output of the transformer 9. The previously enunciated conditions are thus realized.

The transformer 9 can be connected to the transmission line, or can act upon aradio transmitter.

In Fig. 2 showing the receiving end, a transformer H is represented which receives the audible impulses furnished by the transmission line (eventually after amplification, limitation, filtering, etc.) or furnished by the radio receiver.

These impulses are detected in the tube l2, which operates as a grid cut-off or limiter tube. To this end, tube I2 is biased by the source (3 so as to permit plate current to flow only at peaks of the control impulses. The grid circuit of said tube contains a resistance 14 having a very high value so as to limit the amplitude at the appearance of grid current. The anode of the tube 12 is connected across a resistance to the direct current source l6. Capacitor l! in shunt with resistor [5 provides a filtering action. Variations in the anode potential of the tube I2 are transmitted across a variableresistor l8 to the distributor switch l9 which rotates in synchronism with the distributor 2 of Fig. 1. This distributor also establishes a contact at each telegraphic time, but alternatively on one of the two diametrically opposite brushes a, b, which are mounted on one support so as to be phase-ad- J'usted as a unit.

These brushes are connected to two identical resistances 20, whose common point is connected to ground across the direct negative biasin source 2|. The brushes are connected also to the grids of two triodes 22, whose anodes are A tape perforation in one row is, thereconnected to the battery 23 across the coils of a polarized relay 24. The relay contacts 26 control the printer, or translator.

The operating mode is likewise easily understandable. In the absence of impulses coming from the line, the current of the tube I2 is zero and the anode of this tube is at the potential of the source l6. Under these conditions, when the sectors of distributor l9 move in front of the brushes, a current taking the path l6, l5, l8, I9, 20 and 2i establishes itself. The potential drop at the terminals of 20 opens successively the one and the other one of the two tubes 22, and the relay 24 see-saws alternatively from one position to the other one. When an impulse manifests itself in II, the potential of the anode l2 drops to a much'lower value and the grids of the tubes 22 are no longer free. The relay 24 thus remains in the previous position. The position of the brushes a and b is obviously controlled in a manner such that the contacts are established in a and b, at the moment in which the impulses can be produced. Hence, also the previously enunciated conditions are realized.

The mode of operation of receiving telegraphic code will now be described in greater detail with reference to Figs. 3 to 8 inclusive ofthe drawings.

Because of the rotation of the ticker l9 shown in Fig. 2, the relay 24 alternately shifts the contact reed from one position to make contact with a fixed contact 25a to the other fixed contact 26b in time sequence with the telegraphic work period. This contact reed movement is prolonged as long as the primary of the transformer ll does not receive impulses. Fig. 3 shows the time periods number I, 2, 3, 4, 5, etc. each period corresponding to a telegraphic period and shown by the abscissae plotted against the amplitudes of the reed of relay 24 indicated by the ordinates and which are assumed to correspond in upward direction to the making of contact 28a and in downward direction to the making of contact 26b. In the example that has been chosen contact 26a is closed at the beginning of each odd telegraphic period or odd multiples thereof, whereas the contact 2612 is closed at the beginning of each even telegraphic period.

Let us now suppose, as is indicated by Fig. 4, that an impulse of brief duration in comparison with the telegraphic period or rate has been fed into the transformer II at the beginning ofsuch period 8. As outlined above the relay 24 which at this instant would rock toward the contact position 26b stays in the contact position 2511 because of the non-block (or cutoff) condition of tube 22 corresponding thereto. At the beginning of the telegraphing period 9 the relay 24 which is in position 26a stays therein; in fact, this is the situation regardless of whether at that instant an impulse reaches the transformer H or not. In short, the arrival of an impulse at the beginning of period 8 has the result of replacing the portion of cdefghij shown by Fig. 3 for the portion indicated by Fig. 4 as cdii, in other words, to cause the appearance of a dash di having a length equalling three times the telegraphic period. In the same way the arrival at the transformer ll of an impulse at the beginning of telegraphic period l3, for instance, as shown by Fig. 5 there results in the appearance of a blank space kl the length of which amounts to three times the telegraphic period, the same extending from the beginning of the time sequence [2 to the end of the telegraphic period I l. The arrival of an impulse at the beginning of the telegraphic period Hi would remain ineffective as regards movement of relay 24 for the same reasons as hereinbefore indicated. But if an impulse does come in at the beginning of period it would extend to m, that is to say, to two telegraphic periods, the blank k 1.

In a practical application of the method outlined above suppose that the words I am are intended to be transmitted in Morse code as shown by Fig. 6. Fig. 7 represents the impulses (assumed to be infinitely brief for the sake of simplifying the illustration) required to trans mit the blank or space five telegraphic period separating the words I and am, the dash of letter a, the two dashes of letter m and the blank of three times the telegraphic period separating the latters a and m.

Fig. 8 represents the movement of relay 24 by action of the above mentioned impulses.

It will be noted that the single dot representative of the letter I coincide with the dashes that precede, corresponding to the rocking or shifting motion of the reed of relay 24 in the absence of impulses. Similarly the letter m may as one wishes be taken for a letter g, for a z or for a numeral 7. In order to avoid these inconveniences all that is necessary is to provide in actual operation the sending of the conventional signals at the beginning and the end of a message. If the series of impulses as shown by Fig. 7 is shifted an odd number of telegraphic periods in the right-hand or left-hand direction, the dashes Fig. 8 become the blanks and vice versa. However, no confusion is liable to be caused, for the fact that five telegraphic periods could be nothing else but spaces or blanks. It would also be feasible to provide for the conventional beginning and end signals of a message a dash (or a blank) amounting to 9 telegraphic periods, that is to say, a sequence of four impulses spaced two periods apart. One would thus be able immediately to receive the portion (either the upper or the lower) of Fig. 8 corresponding to the dashes.

I claim:

1. A system for the transmission of intelligence comprising a receiver having means normally responsive to locally derived periodic electrical impulses, said impulses being delivered during alternate ones of a succession of elemental signalling periods, said means being shiftable by said impulses to a condition of marking sig-. nificance and being shiftable during intermediate periods to a condition of spacing significance, a transmitter having means for sending to said receiver signals each element of which is limited in duration to a discrete one of said elemental signalling periods, means for codifying the intelligence to be transmitted in accordance with dots, dashes and spaces which are commensurate with said elemental signalling periods and odd multiples thereof, and means at the receiver for combining the effects of the locally derived impulses and the transmitted impulses in such manner 6 that the responsive means is caused to follow and to signify the dots, dashes and spaces of the codified intelligence.

2. A telegraph system for transmitting brief marking impulses spaced apart by integral multiples of-an elemental period, comprising at one location a two-position contact member, having a pair of contacts oppositely disposed with respect to an arm and adapted to alternately engage said arm, a distributor switch driven in synchronism with said contact member, a voltage supply source having its positive terminal connected to said distributor switch, an electron discharge device having an anode, a control grid, screen grid and. a cathode, a first resistance connected from a brush on said distributor to the arm of said contact member also to said screen grid, a second resistance connected from said screen grid to said pair of contacts and to the cathode of said electron discharge device, a transformer winding for supplying a, tone frequency having one side connected to a control grid of an electron discharge device through a bias source, the other side of said transformer being connected to said cathode and to said pair of contacts, an output circuit coupled to the anode cathode circuit of said device, a receiver input at another location removed from said first mentioned location, an electron discharge device at said other location having at least an anode cathode and a grid, a connection from said receiver input through a limiting resistor to said last mentioned grid, a resistance connected in series with a source of potential and the anode of said last electron discharge device, and a distributor switch also at said other location and having a pair of spaced brushes, said distributor rotating in synchronism with said first mentioned distributor, a connection from the anode of said last mentioned electron discharge device to a segment on said last mentioned distributor adapted to alternately contact said brushes, a relay, means to connect said relay to the brushes of said distributor at said receiver location for receiving the transmitted marking impulses to thereby hold said relay in a position to which it was set during the previous elemental period.

3. A telegraph system in accordance with claim 2, characterized in that said relay comprises a push-pull electronic relay.

4. A telegraph system having means for transmitting marking and spacing signals in accordance with the message to be transmitted, and means in synchronism with said first mentioned means for transmitting at the beginning of the message an impulse which is of a duration shorter than the duration of either the marking or spacing si nals during the occurrence of said signals.

HEZNRI CI-HREIX.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 153,063 Foot July 14, 1874 1,875,935 Sandeman Sept. 6, 1932 FOREIGN PATENTS Number Country Date 376,820 Great Britain July 18, 1932 864,171 France Apr- 21, .1946, 

